Oil Drain Access Panel

This was just a quick fun mod I did soon after I got the car to make servicing a bit easier. I stick to a 5k mile oil change interval with filters changed every 10k miles but during track season I'm usually changing just the oil more frequently. The normal procedure for that of course is to remove the 15 or so T25 torx to drop the plastic undertray and then remove the bolts for the aluminum tray. That's all too much work :) Instead I've added a small access panel directly under the oil drain plug and that's attached to the car with quarter-turn fasteners. So for a quick oil drain all I need for tools is the 19mm wrench for the drain plug.

The quarter turn fasteners were sourced from Pro-Bolt. 14mm D-ring with slide on clips.
http://www.probolt-usa.com/stainless-steel-qr-studs-s-lide-clips-d-ring-14mm-pack-x-10-mssqrpackslide1014.html

Some quick pics and measurements for how I did this. You'll note the opening is slightly odd shaped. The original plan was to put a second NACA duct here instead of just a flat cover so that it wouldn't even be noticeable as an access panel. So this panel is quite oversized compared to what's really required.

First a pic of the access hole in the undertray so you can get yourself oriented with where to cut. The left side would be towards the front of the car. There's that big open slot that draw in air that is then deflected up the back side of the engine (note I'd love to build some actual duct work here to direct the air to the turbo area and build a proper chimney, maybe some other day).

The oil drain plug is right at the rear edge of the opening, near the deflector, so really you just need to cut an opening from the very edge of the deflector up a few inches. Be careful to leave enough space around the edges for the quarter-turn fasteners. Mine are about 2cm wide.

That leaves a space about 8.5cm wide. Probably wider than needed but nice to have space to swing the wrench.

And with the cover in place. This is just stock aluminum sheet from the local hardware store and cut to size. I possibly should have left the label maker in the house that day :)
And again, the sizing was all intended to use a NACA duct for the cover so if you're doing this you can just cut a smaller rectangular opening.

And finally a picture of the undertray in place showing the available access. This really only works because the TTRS drain plug is at an angle so the flow of oil just misses the back edge of the undertray. Really all that's needed is an 8.5 x 5 cm hole.